Use symbol_level=1 also for MSVC dbg bots.

See https://webrtc-review.googlesource.com/c/src/+/155440/5#message-4c2c222ce7043f9c9c6936a38545bef82610132a for more info.

Bug: webrtc:11011
Change-Id: If09de0fe890d51f2f8615296e740c3575e21544c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/157280
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29512}
diff --git a/tools_webrtc/mb/mb_config.pyl b/tools_webrtc/mb/mb_config.pyl
index 024c2ae..480b608 100644
--- a/tools_webrtc/mb/mb_config.pyl
+++ b/tools_webrtc/mb/mb_config.pyl
@@ -329,13 +329,13 @@
       'clang', 'openh264', 'release_bot', 'x64',
     ],
     'win_msvc_debug_bot_x86': [
-      'no_clang', 'debug_bot_no_goma', 'x86', 'no_lld',
+      'no_clang', 'debug_bot_no_goma', 'x86', 'no_lld', 'minimal_symbols',
     ],
     'win_msvc_release_bot_x86': [
       'no_clang', 'release_bot_no_goma', 'x86', 'no_lld', 'minimal_symbols',
     ],
     'win_msvc_debug_bot_x64': [
-      'no_clang', 'debug_bot_no_goma', 'x64', 'no_lld'
+      'no_clang', 'debug_bot_no_goma', 'x64', 'no_lld', 'minimal_symbols',
     ],
     'win_msvc_release_bot_x64': [
       'no_clang', 'release_bot_no_goma', 'x64', 'no_lld', 'minimal_symbols',